<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
        {{msg}}
        <button @click="change">按钮</button>
    </div>
    <script src="./vue.js"></script>
    <script>
        let vm = new Vue({
            el:"#app",
            data:{
                msg:123
            },
            methods:{
                change(){
                    console.log(this)
                    this.msg = 234
                }
            }
        })
        // 在实例方法中如何改变 状态  this.xx = 值
    </script>
</body>
</html>